Problem: Simplify the expression. $(-7n^{4}+2n^{2}-5n)(-6n^{3}+4n^{2})$
First use the distributive property. $ - 7 n^4 (-6 n^3) - 7 n^4 (4 n^2) + 2 n^2 (-6 n^3) + 2 n^2 (4 n^2) - 5 n (-6 n^3) - 5 n (4 n^2) $ Simplify. $ 42n^{7} - 28n^{6} - 12n^{5} + 8n^{4} + 30n^{4} - 20n^{3} $ $42n^{7}-28n^{6}-12n^{5}+38n^{4}-20n^{3}$ Identify like terms. $ { 42n^{7}} {- 28n^{6}} {- 12n^{5}} {+ 8n^{4}} {+ 30n^{4}} {- 20n^{3}} $ Add the coefficients. $ { 42n^{7}} { -28n^{6}} { -12n^{5}} {+ 38n^{4}} { -20n^{3}} $